"Some people believe football is a matter of life and death, I am very disappointed with that attitude. I can assure you it is much, much more important than that". Bill Shankly
"You're playing worse and worse every day and right now you're playing like it's next month".Herb Brooks

Hard to name a place, there are many beautiful places in WOW world.
Winterspring, Ferelas, Howling Fjord, Grizzly Hills, Jade Forest, Kun Lai Summit... there are many many.
It won't ever happen propably though, this would be so nice thing to sink all those millions of gold i stole from poor raiders needing their gem upgrades.

if they were to put in player housing, unless they have it completely out of phase for all players not in the group with that player it couldn't happen as there would be houses everywhere and im pretty sure blizz wouldn't want that, the only other option would have an instance in the cities where a player would enter as their own house or another way would have a number of houses already made in various locations that are seperate instances where a player could purchase the one they like the best.

Some folks scoff at the idea like it's a done deal Blizz can only do it one way. Blizzard's had 10+ years of seeing player housing in other MMOs (the ones that have the feature) so it's not like they don't have ideas to go on.

Here are two ways I could see them doing it:

* Pioneering: Depending on where the land you want to settle is located you will first buy a homeowner's license in Stormwind. After that you will be directed to visit a realitor in the area of the land you wish to buy. If the area is a (literally) being fought over you're directed to a quest hub for that area. In either case you'll be allowed to have your land but first you'll have to secure and clear the area. Once you've marked the spot a group of peons/grunts show up and start building your house.

While they're doing that the foreman will tell you there's some stuff you can do while your home is being built. You'll then get a couple of quests, some based on your class and some based on your profession. After you finish the first round of quests and turn them in enemies attack but with you there, they're all defeated. Afterward the Foreman tells you it might be a good idea to hire some muscle and sends you to the nearest faction quest hub to talk to the garrison there. If you quested there they'll give you the manpower free of charge. If not they will ask you to help them out to earn their trust. When you get back your house is done and your house is on the map.

The Foreman tells you that you should talk to the realitor when you want to expand, etc. He also says as your how gets bigger you can invite roomates to stay in the house. The more expansions you buy the more interesting things you can do. For example if you buy the Portal Matrix you can use it to instantly travel from your house to any of the faction capitals plus Shattrath, Dalaran and your faction's Shrine on Pandaria. Buying a tombstone adds a repawn point to your home. If your house is in a contested area you automatically get a cloaking enchantment making it invisible to the other faction. Be warned: If you're flagged for PvP and you go to your house it will be visible to the other faction! And they can attack it. After doing considerable damage the other side can attempt to capture the Alliance/Horde banner outside your house. If they manage to take it your house will be destroyed. For a fee, you can rebuild.

Settlements: I'd say for this think Warcraft III/StarCraft II and Civiliation. The process is similar to forming a guild. The leader buys the conscript of intent and has 5 or more people sign it as co-founders of the settlement. Once the signature requirement is met you will be able to build the town on any of the four continents plus Outland. Once you've picked a suitable spot for the town hall it will be built instantly along with a quest board specifically for building the new settlement. A series of quests will be made available, some depending on class, role and/or known professions. Among them include securing raw materials for building the town, building a lumber yard and other stuff.

Once resources are secured the nexy phase will be securing the settlement. Direct your workers to build a perimeter (which can be upgraded later) around the settlement. Once this is done it will be time to build a barracks. After the barracks is built some of the peons will automatically become guards to protect your settlement from attack. Now it's time to build housing! This part is player specific. Players can share a house if they'd like as well. After that's taken care of, now it's time to establish an economy. After the profession-specific buildings have been built you'll be able to use the buildings to sell things. As a shareholder in the settlement you get a cut of the profits. The final phase is establishing trade routes to other settlements or faction-controlled outposts. All player members will be able to take the quest. Once three or more people have completed the Trade Route quest your town will appear on the world map and a flightmaster will move in.

From here you can visit the town hall to build additional improvements such as a Mage Tower (Portals), Auction House, Harbor (if next to water), A Graveyard, Guild Master Services, an Inn and even more guards. to protect your town from the unsavory. Unlike the above scenario the other faction can see settlements as soon as they're built. Only the town's leadership can flag it for PvP (unless it's on a PvP server in which case it's automatically flagged). If the other side succeeds in destroying the Town Hall and the Alliance/Horde Flag hanging outside it the town will belong to the other faction.